scripts/oe-package-browser: Fix after overrides change

After the overrides change, the format of pkgdata changed and this
usage of configparser no longer works. This change is a bandaid to make
things work but the pkgdata format isn't very similar to ini files
so this may need to be reimplmented in a better way in the long run.

[YOCTO #14619]

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>